Nail Locking Systems

ABSTRACT

A system for fixing a fracture near a joint of a bone comprises (a) an intramedullary device including a longitudinal body and a head, the longitudinal body extending from a proximal end to a distal end, the head being attached to the proximal end of the longitudinal body; and (b) a plate implantable into a head portion of the bone to provide support to a joint zone, the plate engageable with the intramedullary device. The plate is substantially U-shaped and includes a midsection and a pair of arms extending from the midsection, the pair of arms forming a space therebetween, the space sized and shaped to accommodate the head of the intramedullary device.

PRIORITY CLAIM

The present application claims priority to U.S. Provisional ApplicationSer. No. 61/175,555 filed on May 5, 2009 entitled “Nail LockingSystems,” the entire disclosure of which is incorporated herein byreference

BACKGROUND

The present invention relates to systems for bone fixation and, inparticular, to an intramedullary metaphyseal fracture stabilizationsystem.

A fracture in the shaft of a long bone may be treated by the insertionof an intramedullary nail or other device into the medullary canal.Intramedullary fracture fixation is advantageous because it providesstability along a length of the bone. A fracture near a joint such as,for example, a fracture in a metaphyseal zone, however, is generallyfixed with screws and plates rather than intramedullary devices. The useof screws and plates alone, however, reduces the support and stabilityof the bone, which may result in a fracture collapse from forces orpressures exerted on the bone.

SUMMARY OF THE INVENTION

The present invention relates to a system for fixing a fracture near ajoint of a bone. The system comprises (a) an intramedullary deviceincluding a longitudinal body and a head, the longitudinal bodyextending from a proximal end to a distal end, the head being attachedto the proximal end of the longitudinal body; and (b) a plateimplantable into a head portion of the bone to provide support to ajoint zone, the plate engagable with the intramedullary device. Theplate is substantially U-shaped and includes a midsection and a pair ofarms extending from the midsection, the pair of arms forming a spacetherebetween, the space sized and shaped to accommodate the head of theintramedullary device.

In a special embodiment the plate includes a first portion implantableinto the bone and a second portion fixable to a surface of the bone, thefirst portion being substantially U-shaped and including a midsectionand a pair of arms extending from the midsection, the pair of armsforming a space therebetween to accommodate the head of theintramedullary device, the second portion being sized and shaped to fixa fracture of the bone.

In a further embodiment the first portion of the plate lies in a planesubstantially perpendicular to a plane in which the second portion islying.

In again a further embodiment the second portion includes a plurality ofopenings, the plurality of openings sized and shaped to accommodate bonefixation elements therethrough.

In another embodiment the head of the intramedullary device includes aplurality of recesses, each recess extending about at least a portion ofa perimeter of the head, the recess being sized and shaped toaccommodate an inner surface of the plate, preferably at the midsectionbetween said pair of arms.

In another embodiment the intramedullary device has one or more openingsextending laterally through the head of the intramedullary device.

In yet another embodiment said system further comprises a bone fixationelement insertable into the opening of the intramedullary device to fixa fracture of the bone.

In again another embodiment the bone fixation element is a locking headscrew and the opening of the intramedullary device preferably has athread.

In yet another embodiment said intramedullary device has at least twoopenings whose central axes are not parallel to each other andpreferably are flaring outwardly or converging for providing support tothe joint surface.

In a further embodiment said plate has an upper and a lower surfacewhich together have a surface area of 190 to 320 mm², preferably 210 to270 mm². Typically, said upper and lower surface together have a surfacearea of 2×120 mm²=240 mm².

In a further embodiment said plate has—measured in the plane of theplate—a minimum diameter of two times, preferably three times thediameter of the intramedullary device. Typically, said minimum diameterof said plate is 12 mm.

In again a further embodiment said plate has means for clipping theplate to the intramedullary device.

In another embodiment said pair of arms of said plate is configured as asnap-on mounting, preferably as a circlip ring. Said pair of armsincluding said circlip ring can be configured similarly to a Seegercirclip ring.

In another embodiment the system comprises several plates engageablewith the intramedullary device on different heights of theintramedullary device whose arms are preferably oriented in differentdirections.

In again another embodiment said intramedullary device is anintramedullary nail, preferably with one or more transverse lockingholes.

In accordance with another aspect of the invention, a method is providedwhich comprises:

inserting an intramedullary device into a medullary canal of the bonevia a fracture zone of the bone, the intramedullary device including alongitudinal body and a head, the longitudinal body extending from aproximal end to a distal end, the head being attached to the proximalend of the longitudinal body;

implanting a substantially U-shaped plate, including a midsection and apair of arms extending from the midsection, the pair of arms forming aspace therebetween, into the bone so that the pair of arms forming aspace therebetween engagingly accommodate the head of the intramedullarydevice.

In a special embodiment of the method said plate is clipped or securedto said intramedullary device.

In another embodiment of the method several plates are engaged with theintramedullary device on different heights of the intramedullary device

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side perspective view of a system according to afirst exemplary embodiment of the present invention;

FIG. 2 illustrates another side perspective view of the system of FIG.1, rotated 90 degrees about a longitudinal axis of the system;

FIG. 3 illustrates a top perspective view of the system of FIG. 1;

FIG. 4 illustrates a side view of an intramedullary device according tothe system of FIG. 1;

FIG. 5 illustrates another side view of the intramedullary device ofFIG. 4, rotated 90 degrees about a longitudinal axis thereof;

FIG. 6 illustrates a top view of a plate according to the system of FIG.1;

FIG. 7 illustrates a side view of the plate of FIG. 6;

FIG. 8 illustrates a side view of a first bone fixation elementaccording to the system of FIG. 1;

FIG. 9 illustrates a side view of a second bone fixation elementaccording to the system of FIG. 1;

FIG. 10 illustrates a side view of a system according to a secondexemplary embodiment of the present invention;

FIG. 11 illustrates another side view of the system of FIG. 10, rotated90 degrees about a longitudinal axis thereof;

FIG. 12 illustrates a top view of a plate according to the system ofFIG. 10;

FIG. 13 illustrates a side view of an embodiment of the intramedullarydevice according to the invention coupled to a guiding device used in anembodiment of a surgical technique according to the invention;

FIG. 14 illustrates a side view of the embodiment of the intramedullarydevice of FIG. 13 inserted into the medullary channel;

FIG. 15 illustrates a side view of the embodiment of the intramedullarydevice of FIG. 13 during preparation for implantation of the plates;

FIG. 16 illustrates a side view of the embodiment of the intramedullarydevice of FIG. 13 during insertion of a plate;

FIG. 17 illustrates a side view of the embodiment of the intramedullarydevice of FIG. 13 with the first and second bone fixation elementsinserted;

FIG. 18 illustrates a side view of the embodiment of the intramedullarydevice of FIG. 13 after removal of the guiding device; and

FIG. 19 illustrates perspective view of the embodiment of theintramedullary device of FIG. 13 with the guiding device removed.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and the appended drawings, wherein like elementsare referred to with the same reference numerals. The present inventionrelates to systems for bone fixation. In particular, exemplaryembodiments of the present invention describe an intramedullarymetaphyseal fracture stabilization system. It should be noted however,that the present invention is not limited to metaphyseal fractures. Forexample, it will be understood by those of skill in the art that theexemplary embodiments of the present invention may also be used tostabilize a diaphyseal fractures by inserting an additional bonefixation element, such as a screw, in the diaphyseal zone. It shouldalso be noted that the use of the terms proximal and distal do not referto a specific direction, but are used to refer to a direction toward(proximal) and away from (distal) a surgeon or other user of the system.

As shown in FIGS. 1-3, a system 100 according to the present inventionis adapted for the treatment of fractures near joints and comprises anintramedullary device 102 sized and shaped for insertion into amedullary canal of a bone 106, and at least one plate 104 insertableinto a fracture zone of the bone 106. The plate 104 engages theintramedullary device 102 so that the plate 104 provides support to thejoint area like a stabilization plateau. The system 100 furthercomprises first and second bone fixation elements 108, 110,respectively, with the first bone fixation element 108 stabilizing afractured portion of the bone 106 while the second bone fixation element110 fixes the intramedullary device 102 at a desired position within themedullary canal of the bone 106.

As shown in FIG. 4, the intramedullary device 102 includes alongitudinal body 112 and a head 114 attached to a proximal end 116 ofthe longitudinal body 112. The head 114 includes a plurality of recesses118 on an outer surface 120 of the head 114, each of the plurality ofrecesses 118 extending about at least a portion of a perimeter of thehead 120 to engage the plate 104. The intramedullary device 102 mayfurther include a first opening 122 extending laterally through the head114 to accommodate the first bone fixation element 108. The firstopening 122 may extend through the head 114 substantiallyperpendicularly to a longitudinal axis of the intramedullary device 102.Alternatively, the first opening 122 may extend through the head 114 ata non-perpendicular angle relative to the longitudinal axis as shown inFIG. 5. In a preferred embodiment, the first opening 122 may be angledat approximately 30 degrees relative to the longitudinal axis, but maydeviate from this angle by up to ″15 degrees. The angle of the firstopening 122 may be selected to correspond, for example, to a position ofa fracture to be treated. Additionally, the first opening 122 mayinclude a threading 126 along an inner surface thereof for engaging aportion of the first bone fixation element 108. It will be understood bythose of skill in the art that the head 114 of the intramedullary device102 may include more than one first opening 122.

The intramedullary device 102 may also include one or more secondopenings 124 extending laterally through the longitudinal body 112 andlocated along a length of the longitudinal body 112. Each second opening124 is sized and shaped to accommodate the second bone fixation element110, which fixes the intramedullary device 102 at a desired positionwithin the medullary canal of the bone 106. The second opening 124 mayextend through the longitudinal body 112 at an angle relative to thelongitudinal axis of the intramedullary device 102. In a preferredembodiment, the second opening 124 may be angled at approximately −30degrees relative to the longitudinal axis, but may deviate from thisangle by up to ″15 degrees, to provide additional stability for thesecond bone fixation element 110 inserted therethrough. In a preferredembodiment, the second opening 124 may be located at the proximal end116 of the longitudinal body 112. However, it will be understood bythose of skill in the art that the second opening 124 may be locatedanywhere along a length of the longitudinal body 112. It will also beunderstood by those of skill in the art that the intramedullary device102 may include more than one second opening 124.

In a preferred embodiment, as shown in FIGS. 5-6, the plate 104 may besubstantially U-shaped such that a pair of arms 130 extend from amidsection 128. The pair of arms 130 and the midsection 128 may beintegrally formed as a single unitary construction. The arms 130 extendfrom the midsection 128 forming a space 132 between the pair of arms130. The space 132 is preferably sized and shaped to accommodate a widthof the head 114 of the intramedullary device 102. An inner surface 134of the midsection 128 is sized and shaped to be accommodated in one ofthe recesses 118 of the head 114 to lock the plate 104 in a desiredposition relative to the head 114. A length and/or a width of each ofthe arms 130 may vary depending on a desired angular orientationrelative to the longitudinal axis of the intramedullary device 102. Itwill be understood by those of skill in the art that the U-shapeprovides wide support of the joint zone, minimizing the possibility ofbone splintering. However, it will also be understood by those of skillin the art that a variety of shapes may be utilized for the plate 104 solong as the plate 104 is engagable with one of the recesses 118 of thehead 114. For example, the plate 104 may be asymmetrical such that oneof the pair of arms 130 is longer than the other. Alternatively, theplate 104 may include the midsection 128 and only one arm 130 extendingfrom an end thereof. It will also be understood by those of skill in theart that more than one plate 104 may be employed with the system 100.

As shown in FIG. 8, the first bone fixation element 108 may be anystandard bone fixation element that is insertable through the firstopening 122. The first bone fixation element 108 may be, for example, ascrew or a pin, including a shaft 136 and a head 138. The head 138 mayinclude a threading 140 along an outer surface 142 thereof for engagingwith the threading 126 of the opening 122. Thus, the head 138 of thefirst bone fixation element 108 may be locked to the intramedullarydevice 102 such that the shaft 136 may fix the fracture in the bonerelative to the medullary canal. It will be understood by those of skillin the art that the shaft 136 may also include a threading along atleast a portion of a length of the shaft 136. As described above, thefirst bone fixation element 108 may be fixed at an angle relative to theintramedullary device 102. It will also be understood by those of skillin the art that more than one first bone fixation element 108 may beemployed with the system 100.

As shown in FIG. 9, the second bone fixation element 110 may also be anystandard bone fixation element, such as, for example, a screw or pin, solong as the second bone fixation element 110 is capable of fixing theintramedullary device 102 at a desired position within the medullarycanal of the bone 106. The second bone fixation element 110 may includea shaft 144 and a head 146, however, the head 146 is not required to belocked to the intramedullary device 102 and does not necessarily includea threading thereabout. As described above, the locking screw 108 may befixed to the intramedullary device 102 at an angle relative to thelongitudinal axis of the intramedullary device 102, providing additionalstability to the intramedullary device 102. It will be understood bythose of skill in the art that more than one second bone fixationelement 110 may be employed with the system 100.

As shown in FIGS. 10-11, a system 400 according to an exemplaryembodiment of the present invention comprises an intramedullary device402 insertable into a medullary canal of a bone 406 and engagable with aplate 404. The system 400 further comprises a first bone fixationelement 408 for coupling the plate 404 to the bone 406. The system 400may further comprise a second bone fixation element 410 for fixing theintramedullary device 402 at a desired position within the medullarycanal of the bone 406. The intramedullary device 402 may besubstantially similar to the intramedullary device 102 including alongitudinal body 412 and a head 414 attached to a proximal end 416thereof. The head 414 is adapted and configured to engage the plate 404and may include for example, a plurality of recesses 418 for engagingthe plate 404, each of the recesses 418 being configured and adapted toaccommodate a height of the plate 404. The longitudinal body 412 of theintramedullary device 402 may include at least one opening 420 foraccommodating the second bone fixation element 410. The at least oneopening 420 may extend laterally through the longitudinal body 412 toaccommodate the second bone fixation element 410 in a manner similar tothat described in regard to the previous embodiment.

As shown in FIG. 12, the plate 404 includes a first portion 422 and asecond portion 424, which are attached to one another via a neck portion426. The first portion 422 may be substantially similar to the plate 104of the system 100. The first portion 422 may be substantially U-shapedsuch that a pair of arms 430 extend from a midsection 428. A space 432between the pair of arms 430 is sized and shaped to accommodate the head414 of the intramedullary device 402 such that an inner surface 434 ofthe midsection 428 engages one of the plurality of recesses 418.

The second portion 424 is connected to the midsection 428 of the firstportion 422 such that a plane of the first portion 422 is substantiallyperpendicular to the second portion 424. The second portion 424 includesa first surface 436, which faces the bone 406, and a second surface 438,which faces away from the bone 406. The second portion 424 may be aplate for fixing a fracture of the bone 406 externally, while the firstportion 422 is inserted into the bone 406 to provide a support of thejoint zone. Thus, in an operative position, the first portion 420 isinserted into the bone 406 at an angle relative to the head 414 of theintramedullary device 402 such that the inner surface 434 of themidsection engages one of the plurality of recesses 418 of the head 414and the first surface 436 of the second portion 424 abuts a surface ofthe bone 406. The second portion 424 includes at least one opening 440for accommodating the first bone fixation element 408 such that thesecond portion 424 may be fixed to the bone 406. Since the secondportion 424 may externally fix a fracture of the bone 406, it will beunderstood by those of skill in the art that the second portion 424 mayinclude more than one opening 440. Accordingly, it will also beunderstood by those of skill in the art that the system 400 may includemore than one first bone fixation element 408 for insertion into theopening 440. The first bone fixation element 408 may be any fixationelement such as, for example, a screw, blade or pin.

The second bone fixation element 410 may be substantially similar to thesecond bone fixation element 110 of the system 100. The second bonefixation element 410 is insertable through the at least one opening 420to fix the intramedullary device 402 within the medullary canal of thebone 402. Thus, it will be understood by those of skill in the art thatthe second bone fixation element 410 may be any fixation element suchas, for example, a screw, blade or pin. It will also be understood bythose of skill in the art that the system 400 may include more than onesecond bone fixation element 410.

As shown in FIGS. 13-19, a surgical technique for applying the system100, according to an exemplary embodiment of the present inventionincludes inserting the intramedullary device 102 into the medullarycanal of the bone 106, using a guiding device 10 coupled to a proximalend of the device 102, as shown in FIG. 13. The intramedullary device102 may be inserted into the medullary canal of the bone 106 via afracture zone of the bone 106, as shown in FIG. 14. The longitudinalbody 112 of the intramedullary device 102 is positioned within themedullary canal, while the head 114 of the intramedullary device 102 ispositioned substantially within a head portion of the bone 406. Theguiding device 10 may additionally hold the intramedullary device 102relative to the bone 106 until the surgical procedure has beencompleted. Once the intramedullary device 102 has been positioned at adesired location within the medullary canal of the bone 106, the bone106 is prepared for implantation of the plates 104, as shown in FIG. 15.For example, the bone 106 may be chiseled to create space for theinsertion of the plate 104, as would be understood by those skilled inthe art. A chisel 12 may be attached to the guiding device 10 to chiselthe bone 106.

Once a space for the plate 104 has been created, the plate 104 isinserted into the space to be coupled to the bone 106, as shown in FIG.16, providing a wide support for the joint zone. The plate 104 may beinserted into the bone 106 until the inner surface 134 of the midsection128 engages one of the plurality of recesses 118. The plate 104 may beinserted into the bone 106 using a plate guiding device 14, which mayalso be attachable to the guiding device 10 such that the plate 104 maybe inserted in a desired orientation relative to the intramedullarydevice 102. It will be understood by those of skill in the art that morethan one plate 104 may be coupled to the bone 106 as desired to treat aparticular fracture. It will also be understood by those of skill in theart that the plate 104 should be implanted such that the plate 104 doesnot block the first opening 122. After implantation of the plate 104,the first bone fixation element 108 and the second bone fixation element110 are inserted through the first and second openings 122, 124,respectively, as shown in FIG. 17. The first bone fixation element 108is preferably passed through the first opening 122 into to couple atarget fractured portion of bone to the shaft of the bone 106. Thesecond bone fixation element 110 is passed through the second opening124 into a portion of the shaft of the bone 106 to fix theintramedullary device 102 at a desired position within the medullarycanal, as shown in FIGS. 18 and 19.

Although the surgical technique has been described with respect to thesystem 100, it will be understood by those of skill in the art that asubstantially similar surgical technique may be used for the system 400.Additionally, for the system 400, it will be understood by those ofskill in the art, that subsequent to the implantation of the plate 404,the first bone fixation element 408 will be inserted through the opening440 of the plate rather than the intramedullary device 402.

It will be apparent to those skilled in the art that variousmodifications may be made in the present invention without departingfrom the spirit or the scope of the invention. Thus, it is intended thatthe present invention cover modifications and variations of thisinvention provided that they come within the scope of the appendedclaims and their equivalents.

1. System for fixing a fracture near a joint of a bone, comprising: anintramedullary device including a longitudinal body and a head, thelongitudinal body extending from a proximal end to a distal end, thehead being attached to the proximal end of the longitudinal body; and aplate implantable into a portion of the bone to provide support to ajoint zone, the plate being engageable with the intramedullary device,wherein A) the plate is substantially U-shaped; and B) the plateincludes a midsection and a pair of arms extending from the midsection,the pair of arms forming a space therebetween, the space sized andshaped to accommodate the head of the intramedullary device.
 2. Thesystem according to claim 1, the plate including a first portionimplantable into the bone and a second portion fixable to a surface ofthe bone, the first portion being substantially U-shaped and including amidsection and a pair of arms extending from the midsection, the pair ofarms forming a space therebetween to accommodate the head of theintramedullary device, the second portion being sized and shaped to fixa fracture of the bone.
 3. The system according to claim 2, wherein thefirst portion of the plate lies in a plane substantially perpendicularto a plane in which the second portion is lying.
 4. The system accordingto claim 2, the second portion including a plurality of openings, theplurality of openings sized and shaped to accommodate bone fixationelements therethrough.
 5. The system according to one of the claim 1,the head of the intramedullary device including a plurality of recesses,each recess extending about at least a portion of a perimeter of thehead, the recess being sized and shaped to accommodate an inner surfaceof the plate, preferably at the midsection between said pair of arms. 6.The system according to one of the claim 1, wherein the intramedullarydevice has one or more openings extending laterally through the head ofthe intramedullary device.
 7. The system according to claim 6, furthercomprising a bone fixation element insertable into the opening of theintramedullary device to fix a fracture of the bone.
 8. The systemaccording to claim 6, the bone fixation element being a locking headscrew and the opening of the intramedullary device preferably having athread.
 9. The system according to one of the claim 6, wherein saidintramedullary device has at least two openings whose central axes arenot parallel to each other and preferably are flaring outwardly orconverging for providing support to the joint surface.
 10. The systemaccording to one of the claim 1, wherein said plate has an upper and alower surface together having a surface area of 190 to 320 mm²,preferably 210 to 270 mm².
 11. The system according to one of the claim1, wherein said plate has—measured in the plane of the plate—a minimumdiameter of two times, preferably three times the diameter of theintramedullary device.
 12. The system according to one of the claim 1,wherein said plate has means for clipping the plate to theintramedullary device.
 13. The system according to claim 12, whereinsaid pair of arms of said plate is configured as a snap-on mounting,preferably as a circlip ring.
 14. The system according to one of theclaim 1, wherein the system comprises several plates engageable with theintramedullary device on different heights of the intramedullary devicewhose arms are preferably oriented in different directions.
 15. Thesystem according to one of the claim 1, wherein said intramedullarydevice is an intramedullary nail, preferably with one or more transverselocking holes.
 16. A method, comprising: inserting an intramedullarydevice into a medullary canal of the bone via a fracture zone of thebone, the intramedullary device including a longitudinal body and ahead, the longitudinal body extending from a proximal end to a distalend, the head being attached to the proximal end of the longitudinalbody; implanting a substantially U-shaped plate, including a midsectionand a pair of arms extending from the midsection, the pair of armsforming a space therebetween, into the bone so that the pair of armsforming a space therebetween engagingly accommodate the head of theintramedullary device.
 17. The method according to claim 16, whereinsaid plate is clipped or secured to said intramedullary device.
 18. Themethod according to claim 16, wherein several plates are engaged withthe intramedullary device on different heights of the intramedullarydevice.